Preparation, Characteristics Evaluation Of Oleoylchitosan Compound Nanoparticles

Chitosan is inexpensive, non-toxic, hydrophilic, biocompatible and biodegradable and has been used as medical materials for drug delivery systems. A new oleoylchitosan compound nanoparticles system is prepared and the characteristics are evaluated.Oleoyl-chitosan (OCS) is synthesized and examined. OCS nanoparticles are prepared using an O/W emulsification method. Cytotoxicity of OCS is investigated via the red blood cell lysis test and the MTT assay. Rifampicin and doxorubicin, as model drug, are investigated for release properties in vitro. Oleoyl-carboxymethyl chitosan (OCMCS), oleoyl-quaternized chitosan (OQCS), oleoyl-chitosan oligosaccharide (OCSO) are synthesized to improve the solubility of OCS. The PLGA-OCS nanoparticle is prepared using PLGA as hydrophobic core to improve the stability of OCS nanoparticles.OCS with different molecular weight (MW) and degrees of substitution (DS) are synthesized by reacting chitosan with oleoyl chloride. The FT-IR, UV, and 1H NMR suggest the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. These OCS exhibited poor solubility in aqueous acidic solution. The solubility of OCS decreases as the increase of DS and MW. These OCS are not soluble at neutral or alkali pH. All the OCS samples can reduce the surfacee tension slightly. The increase of DS values and decrease of MW can increase the ability of OCS. The viscosity of OCS sharply increases with the increase of concentration, whereas that of unmodified chitosan rises only slightly. This increase is stronger as the increase of DS and MW of the polymer. The viscosity of OCS in HCl is larger than in HAc. The viscosity decreases with the increase of temperature. The hydration property of OCS is good. The hydration property of OCS is lower than CS. As for OCS, some of–NH2 are occupied by oleoyl groups, which decreases the numbers of–NH2 and also the hydrogen bonds between hydrophilic groups and water. The self-assembling properties of OCS are analyzed using the fluorescence probe test, the laser light scattering and the transmission electron microscopy. The results show that OCS molecules tend to assemble when the concentration is higher than about 0.1g/l and this trend increases with the rise of concentration. This tend is stronger as the increase of DS and decrease of MW of OCS. The critical aggregation concentration (CAC) of OCS with DS 5, 11, and 27% are 79.43, 31.6, 10 mg/L, respectively, and the CAC of samples with molecular masses of 20, 38, 300, and 1100 kDa are 50.1, 79.43, 125.9, and 630.9 mg/L, respectively. The addition of CH2Cl2 helps to the formation of nanoparticles. Nanoparticles were prepared using O/W emulsification method. Most of the nanoparticles formed are around 200nm and are of a spherical shape, which indicates that the prepared nanoparticles have good structural integrity. The size of self-aggregates decreased as the DS increased, indicating formation of denser hydrophobic cores in high DS sample. Mean diameter of the polymeric amphiphilic nanoparticles of OCS with DS 5% and 11% were around 327.4 nm and 275.3 nm. The increase of DS and decrease of MW might facilitate the formation of nanoparticles but the DS should be not too large to have a compromise between solubility and viscosity.Rifampicin and doxorubicin, as model drug, are investigated for their release properties in vitro. The FTIR of rifampicin loaded OCS nanoparticles indicate the success of model drug rifampicin to OCS nanoparticles. The loading efficiency increases as the increase of DS and the decrease of MW. The release of rifampicin slower as the DS and MW increased. The release of rifampicin from solution with pH 6.0 and 6.8 was characterized by a faster release than from solution with pH 3.8. The increase of TPP can slow the release of drug. The sample with low concentration of rifampicin release faster and entirely. The FTIR of doxorubicin loaded OCS nanoparticles indicate the success of model drug doxorubicin to OCS nanoparticles. The release speed of doxorubicin of three DS OCS sample is similar. The increase of MW of OCS can slow the release of doxorubicin. The release of doxorubicin is slower in pH 3.8 HAc than in pH 6.8 PBS. The effect of doxorubicin and TPP concentration on release is unconspicuous. The increase of OCS concentration can slow the release of doxorubicin.Cytotoxicity of OCS is investigated via the red blood cell lysis test and the MTT assay. The red blood cell lysis test shows that each sample can be regarded as non-toxic to red blood cells in the solid state, while the cytotoxicity can not be neglected in the solution state and nanoparticles state. The hemolysis rate of most OCS samples is less than 10% which was regarded as non-toxic effect level. OCS exhibits no cytotoxicity to fetal mouse skin fibroblast with the increase of concentration. All the OCS and OCS nanoparticles have good biocompatibility from the cytotoxicity testing. And the biocompatibility of OCS nanoparticles was better than OCS solution. The toxic effect of nanoparticles in the acidic medium may be due to the fully protonation of the primary amino groups. The biodistribution test of OCS nanoparticles suggests the accumulation in spleen and lung. The mucosa test suggests the OCS can adhere and across the stomach and intestine mucosa. The adherence of OCS nanoparticles onto stomach mucosa is stronger than OCS solution,while that onto intestine mucosa is less than OCS solution.Oleoyl-carboxymethyl chitosan (OCMCS), Oleoyl-quaternized chitosan (OQCS), oleoyl-chitosan oligosaccharide (OCSO) are synthesized to impvove the solubility of OCS. The results of FTIR confirm the successful modification. The solubility of OCMCS, OQCS, and OCSO are better than OCS. Three kinds of chitosan derivatives have good biocompatibility and hydration property. Nanoparticles of OCMCS, OQCS and OCSO are prepared using an O/W emulsification method. The TEM conformed nanoparticles have good structural integrity.The PLGA-OCS nanoparticles are prepared using PLGA as hydrophobic core. The effect of PLGA content, OCS concentration, emulsification speed, and H2Cl2 content on the formation of nanoparticles is invisigated. The PLGA content affect the foamation efficiency of slightly. The increase of OCS concentration can decrease the foamation efficiency. The increase of CH2Cl2 concentration can increase the foamation efficiency. The inceease of emulsification speed can increase the foamation efficiency. The increase of emulsification speed can redound to the formation. The incerese of PLGA content, OCS concentration, and CH2Cl2 concentration can redound to the formation of nanoparticles. The Most of the nanoparticles formed are around 200nm and are of a spherical shape.Oleoylchitosan compound nanoparticles had good biocompability and characteristics which could be the ideal delivery systems of active biomaterials.